These investigations focus on the potential of normal and neoplastic cells of the lung to synthesize polypeptide hormones. A pituitary-like cell which has been identified in the lungs of various species might be a stem cell and a target progenitor to lung tumors such as oat cell carcinoma. These tumors are capable of producing bioactive polypeptide hormones. One aspect of this research is to determine what specific hormones are associated with this type of cell and also to determine what regulatory role is served by such hormones in the lung. Since human bronchogenic squamous cell carcinomas are known to produce a large form of adrenocorticotropic hormone, an investigation has been initiated to purify this material from bovine pituitary glands so that a specific radioimmunoassay might be developed and used for early detection of some bronchogenic tumors.